As shown in FIG. 5, the minutia information input device which executes setting of minutia information on the minutiae contained in a latent fingerprint within a fingerprint image may deal with a fingerprint image including an unclear latent fingerprint in some cases.
With the minutia information input device in general, operations for inputting and designating positions of minutiae included in a latent fingerprint are executed by an operator.
In a case of inputting minutia information for an unclear latent fingerprint, first, the operator performs gray-scale value width adjusting processing on the entire fingerprint image to make the latent fingerprint clear as shown in FIG. 6, and then inputs the minutia information as shown in FIG. 3. Note here that the minutia information including minutia positions, minutia directions, and minutia types for each minutia is set for each minutia (FIG. 7). As the minutia information, it is also possible to employ the setting for executing only plotting input for showing the positions of the minutiae.
As described, in a case where the clarification processing is executed on the entire fingerprint image and then the minutia information is inputted, normally, as shown in FIG. 8A, the optimum gray-scale value width utilized for acquiring distinctiveness varies depending on the region of the fingerprint image or the area of the latent fingerprint.
Note here that the latent fingerprint in (a) region of the fingerprint image in FIG. 8A is so unclear that the finger ridgeline shape cannot be recognized, while the ridgeline shape of the latent fingerprint in (b) region appears clearly. The fingerprint image shown in FIG. 8A is outputted and displayed with the display gray-scale width by setting the upper limit value as 255 and the lower limit value as 167, for example.
In such case, the operator clarifies the fingerprint image through setting the gray-scale width (dynamic range) by corresponding to each of the areas of different distinctiveness in the latent fingerprint and inputs the minutia information for the latent fingerprint in the partial region (image region) of high distinctiveness in each of the partial regions.
For example, FIG. 8B shows the state where the gray-scale value width (dynamic range) in the fingerprint image of FIG. 8A is adjusted to be narrowed to “upper limit value 254, lower limit value 244” from “upper limit value 255, lower limit value 167”. As a result, in (d) region, the ridgeline shape of the latent fingerprint appears clearly.
In the meantime, in (c) region as a result of the adjusting processing, a part of the fingerprint ridgeline is white and cannot be observed. Thereby, it becomes a region that is so unclear that the accurate shape of the latent fingerprint cannot be grasped.
Further, FIG. 8C shows the state where the gray-scale value width (dynamic range) in the fingerprint image of FIG. 8B is adjusted to be narrowed to “upper limit value 254, lower limit value 251” from “upper limit value 255, lower limit value 167”. As a result of the adjustment, in (f) region, the ridgeline shape of the latent fingerprint appears clearly. In the meantime, in (e) region as a result of the adjusting processing, a part of the fingerprint ridgeline is white and cannot be observed. Thereby, it becomes a region that is so undistinctive that the correct shape of the latent fingerprint cannot be grasped.
As described, for clarifying the fingerprint image, it is necessary to repeatedly perform the image clarification processing and the minutia input processing at least twice or more for each image region. Thus, in a case of setting the minutia information for a fingerprint image containing a great amount of minutiae or for a great amount of fingerprint images, the number of operation steps and the operation time for the minutia input operation become enormous.
In particular, as described above, there are a large number of steps contained in the operation steps such as performing screen transition by activating a graph showing a histogram of an image from a fingerprint image for adjusting the gray-scale value width in the fingerprint image, adjusting the gray-scale value width on the graph, then activating the fingerprint image screen on which the gray-scale value width is reflected again, and plotting the minutia information. This is troublesome for the operator, and the terminal operation time becomes extremely long.
As a related technique thereof, there is known a fingerprint collation system (Patent Document 1) which: generates fingerprint data containing information regarding minutiae for each fingerprint image; sets minutia information such as positions of the minutiae, the minutia directions, and the like by specifying a common minutia that is a same minutia from the corresponding relations of the minutiae between a plurality of pieces of fingerprint data; and performs fingerprint matching based on synthesized fingerprint data generated based on the minutia information.
Patent Document 1: Japanese Unexamined Patent Publication 2001-344604
However, as evident from the disclosed content thereof, the related technique disclosed in Patent Document 1 described above cannot be applied for fingerprint images including unclear latent fingerprints. Thus, the related technique always requires input operations of the minutia information done by the operator, which is troublesome.
It is an object of the present invention to improve the inconveniences of the related technique described above and to provide a fingerprint minutia display input device, a fingerprint minutia display input method, and a fingerprint minutia display input program, which make it possible for the operator to quickly and simply perform display operations for each minutia position in a fingerprint image.